A variety of different sole constructions are used by the footwear industry. For the most part, each sole construction has characteristics that make it particularly well-suited for specific applications. For example, some sole constructions are selected for their durability, others for their flexibility and comfort, while still others are selected for their aesthetic appeal.
One type of shoe construction is referred to as a welt construction, which is typically a strip of material such as leather or hard rubber used to secure the sole and the upper together. Welt constructions generally provide durability and aesthetic appeal. FIG. 1 is a cross sectional view of a conventional goodyear welt construction. This construction usually includes a welt 10 that connects an upper 12 and a sole 14. The welt 10 often includes a base portion 16 with an upwardly extending rib 18 located toward the center of the base portion and a downwardly extending rib 19 located at the inner edge of the base portion 16. The sole 14 may include an insole 20, a midsole 22, and an outsole 24. The insole 20 typically includes a downwardly extending rib 18 that is used to connect the insole 20, upper 12 and welt 10.
Welt construction typically involves a number of manufacturing operations or steps. Normally, the upper is wrapped around a last and secured to the insole by stapling, stitching, or other fastening mechanism. This step typically provides the upper with a desired shape and is commonly referred to as lasting. Once lasted, the welt is usually secured to the upper and insole by stitches or staples that extend through downwardly extending rib 19, the bottom periphery of the upper 12, and the insole rib 26. The midsole may be secured to the bottom of the upper/insole assembly. Typically, the midsole is attached to the upper/insole assembly by stitching that extends through the base portion 16 of the welt 10 and the midsole 22. Although this construction is believed to be durable and aesthetically appealing, it is generally a heavy construction and typically does not provide flexibility relative to other shoe constructions. Moreover, due to the number of manufacturing operations specified above, the cost of providing a welt construction shoe may be higher than other shoe constructions.
U.S. Pat. No. 6,226,895 to McClelland (“McClelland”) appears to disclose a shoe having a welt that extends around a periphery of the shoe, where the welt secures the upper to the insole and outsole. The shoe seems to show a first stitch extending through the welt, upper, and insole to secure these members together. A second stitch seems to extend through the welt and outsole to secure the welt, upper, and insole to the outsole.
U.S. Pat. No. 6,192,605 to Challant (“Challant”) appears to disclose a molded midsole and a molded welt, where both the welt and midsole are molded into a single unit. The resulting shoe is believed to reduce manufacturing costs without sacrificing benefits of a shoe employing a welt.
Both Challant and McClelland do not appear to relate to a shoe construction that secures the upper to a midsole or outsole without a need for a welt. Further, both references seem to disclose an insole as part of the shoe. construction.
Cementing components of a shoe, such as the upper to the midsole or outsole, often involves a number of manufacturing operations. Typically, there is a surface preparation step where the surfaces to be cemented, or glued, are clean of debris and readied, which may also include roughening. Further, there may be an application step where the cement is applied to the surfaces. This step may also involve measuring and evenly distributing the glue over the surface.
Further, there may be a pressing step where the surfaces are pressed together. Pressing is believed to reduce air that may be trapped between the surfaces and enhances adhesion. Pressing may also include aligning the surfaces so that the peripheries of the components are flush with one another.
Additionally, once the components are pressed together, cementing often requires a waiting period for the cement to cure, or dry. Generally, not only does cementing involve some or all of the above mentioned manufacturing operations, it also involves time, particularly the curing time.
It is believed that the number of steps and time involved, especially if user intervention is required, negatively affects cost and efficiency. The cementing process may be further complicated if the surfaces to be glued are uneven or difficult to reach.
U.S. Pat. No. 4,369,589 to Summey (“Summey”) and U.S. Pat. No. 3,821,827 to Nadler (“Nadler”) appear to disclose a shoe having cement or glue to secure the upper to the midsole or outsole. Summey seems to disclose the pressing and aligning operations as well as user intervention described above. Summey also seems to disclose an insole as a part of the shoe.
What is desired, therefore, is a shoe that may be constructed in a more efficient manner, including reduced manufacturing costs and less manufacturing operations. What is also desired is a shoe that is more flexible to enhance comfort. A further desire is to provide a shoe that is lighter to enhance wearability.